Run publish jobs on ubuntu-latest for npm provenance (#1344)

npm trusted publishing with --provenance rejects Blacksmith runners: the
sigstore bundle records the runner environment as self-hosted and npm only
accepts github-hosted. This is the same failure #1291 fixed; #1292 reverted
it on the theory the culprit was a trusted-publisher filename mismatch, but
the 1.5.29 publish failed with the runner-environment error again. Only the
two publish jobs move; CI stays on Blacksmith.

Author: RhysSullivan

.github/workflows/publish-executor-package.yml

@@ -23,7 +23,7 @@ concurrency:
 
 jobs:
   publish:
-    runs-on: blacksmith-4vcpu-ubuntu-2404
+    runs-on: ubuntu-latest
     permissions:
       actions: write
       contents: write

.github/workflows/release.yml

@@ -15,7 +15,7 @@ concurrency:
 
 jobs:
   release:
-    runs-on: blacksmith-4vcpu-ubuntu-2404
+    runs-on: ubuntu-latest
     permissions:
       actions: write
       contents: write